Women's Health

How Your Menstrual Cycle Changes in Perimenopause - and Why tracking It Matters

Perimenopause is not a single moment—it’s a multi-year hormonal transition that unfolds in stages. One of the earliest and most reliable clues that you’ve entered this phase is a change in your menstrual cycle.

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Understanding how your cycle is changing can help you:

  • Identify where you are in the menopausal transition

  • Understand the hormonal patterns driving your symptoms

  • Choose the most appropriate treatment strategy for your body

  • Decide whether testing may be helpful (especially if you don’t bleed due to an IUD)

Let’s break down what’s normal, what’s not, and how tracking can guide care.


The First Sign of Perimenopause: A Changing Cycle

In your reproductive years, your cycle is typically predictable—often within a 2–4 day window each month.

In early perimenopause, the defining change is:

A cycle that shifts by 7 days or more—earlier or later—compared to your usual pattern.

This may look like:

  • A period arriving 7–10 days earlier than expected

  • A cycle that suddenly stretches 1–2 weeks longer

  • Month-to-month unpredictability

This is often driven by inconsistent ovulation, fluctuating estrogen, and rising progesterone deficiency.


Later Perimenopause: Longer Gaps Between Periods

As you move further into the menopausal transition, the ovaries begin to respond less consistently to brain signals.

In later-stage perimenopause (which may last 1–3 years), you may notice:

  • Skipped periods

  • Cycles that stretch beyond 60 days without bleeding

  • Heavier or prolonged bleeding when periods do return

At this stage, hormone fluctuations are more extreme, and symptoms such as hot flashes, sleep disruption, anxiety, and heavy bleeding often intensify.


Why Cycle Tracking Is So Powerful

Tracking your cycle is not just about dates—it helps determine:

1.  Where you are in the transition

  • Shorter or variable cycles → earlier perimenopause

  • Long gaps (>60 days) → later perimenopause

2.  Which treatment options may be most supportive

For example:

  • Heavy + more frequent periods
    → often seen in early perimenopause
    → a hormonal IUD may be a helpful option if blood loss is leading to other issues and can’t be controlled naturally - ie. anemia!

  • Heavy + infrequent periods
    → often seen in later perimenopause
    → an IUD may not be the best fit if the heaviest is infrequent and menopause is now expected in 1-3 years version who knows how many years!
    → other hormone or non-hormonal strategies may be more appropriate


Without tracking, these patterns are easy to miss—and treatment choices may not match your true hormonal stage.


What If You Don’t Get a Period Because of an IUD?

If you have a hormonal IUD and no longer bleed, cycle tracking isn’t possible—but this is when lab testing can help.

FSH Testing in Perimenopause:

FSH (follicle-stimulating hormone) rises as the ovaries become less responsive. In late-stage perimenopause and menopause:

  • FSH levels are often consistently above 25 IU/L

To confirm a menopausal transition when cycles are absent:

  • Two FSH levels >25 IU/L

  • Drawn at least 3 months apart

This can help determine:

  • Whether you are still in perimenopause

  • Whether you may be transitioning into menopause

  • Which therapies are safest and most appropriate


The Takeaway

Your cycle is one of your most valuable hormonal data points.

Whether you’re:

  • Noticing unexpected changes

  • Skipping periods

  • Bleeding more heavily

  • Or no longer bleeding due to an IUD

Tracking (or testing when needed) allows us to:

  • Identify your stage

  • Understand your symptoms

  • And personalize your treatment plan


Perimenopause is not something to “wait out.” With the right insight, it can be navigated with clarity and confidence.

Perimenopause 101 - How to tell you are in it

Diagram from Lara Briden’s Hormone Repair Manual

Perimenopause is a gradual transition that typically begins in a woman's 40s, marking the lead-up to menopause. It's important to note that for women over 45, perimenopause is typically a clinical diagnosis and does not require lab assessment for confirmation. To help you recognize if you're entering this phase, here are some key signs to look out for:

  • Changes in menstrual patterns: Your periods may become irregular, with cycles becoming longer or shorter. You might still have periods, but the consistency and frequency may vary. Often your period becomes shorter before it gets less frequent.

  • New physical symptoms: You may experience hot flashes, night sweats, or changes in your skin and hair. Vulvar and vaginal symptoms can also occur while you're still menstruating. You may also have an exacerbation of pre-existing symptoms such as breast tenderness.

  • Insomnia and sleep changes: As your hormones fluctuate your sensitivity to that could cause worsening of sleep, either a few days before your period or throughout the cycle.

  • Mood changes: Some women notice shifts in their emotional state, including increased irritability or mood swings. It's important to note that while mood changes are common, severe depression should be addressed with a healthcare provider.

To better understand and manage your perimenopause journey:

  • Track your symptoms: Keep a record of your menstrual cycles and any new symptoms you experience. This can help you identify patterns and provide valuable information to your healthcare provider.

  • Get appropriate testing: Again hormone testing does not diagnose perimenopause however getting baselines of B12, ferritin, liver enzymes, lipid panels can be helpful to assess your overall health and cardiovascular risk (one thing we care about the most!)

  • Consider your family history: Ask your mother about her menopause experience, as there can be genetic similarities. Ask about family history of osteoporosis and cardiovascular disease. These areas of health are important to monitor in women’s health.

  • Seek expert help: Consider seeing a menopause practitioner who specializes in this life stage to get targeted support and avoid misdiagnosis.

Remember, every woman's experience with perimenopause is unique. By staying informed and proactive about your health, you can navigate this transition more smoothly and ensure you receive appropriate care and support.

Low Energy? What blood work an ND may want to see.

If I was to ask you to rate your energy on a scale of 1-10 (10 being great) what would you say? If you said lower than 5/10, even after a good nights sleep, it is something that should be addressed.

I like to review blood work first when fatigue is a concern, as a few common nutrient and hormone deficiencies can be the culprit. The reference ranges I refer to may be slightly different than your MD for a few reasons.

  1. I want to optimize your levels to sustain better energy.

  2. I am referring to the newest reference range recommendations that will hopefully be reflected in blood work soon.

  3. I see results when patients levels reach a certain level.

So what blood work do I like to see and what levels should they be at? This may vary slightly depending on someone’s health history.

  • Vitamin B12 - This should be above 200 pmol/L, ideally above 450 pmol/L.

  • Ferritin - You have iron deficiency anemia if your ferritin level is below 30 ug/L. Unfortunately, this is becoming more and more common in today’s society. A full iron panel is not often needed.

  • TSH - Your thyroid stimulating hormone should be between 0.8-2.5 mIU/L. This can fluctuate during times of stress or hormone changes. Medication is not often needed until the level gets much higher, however supporting adrenals (stress hormones) and the thyroid gland if out of this range can help.

  • Morning Cortisol - Between 7-9am your level should ideally be between 450-550 nmol/L. Cortisol is an essential hormone that plays many important roles, including regulating your body's stress response. If it is low you are most likely suffering from burnout!

There are several reasons why someone may be deficient in any of these and it is important to address the cause as well as supplement for the deficiency.

Take a look at your most recent blood work. What are your levels like? I’m happy to help improve them and ultimately your energy!

Burnout & Energy Crashes - Unpacking Reasons Why

burnout

Burnout or fatigue...a very common concern I see in practice. 😞😴 But I promise you don't have to feel like this forever! ⠀
If you have been feeling emotionally and physically drained for awhile now let's dig into some common reasons why this may be.

1. Nutrient deficiency

Have you had blood work done to check nutrient levels lately? Some common blood work I like to see for those who are struggling with energy are:⠀⠀

  • ferritin (your iron stores)⠀

  • B12⠀

  • Thyroid panel - additional symptoms may point us to look into this⠀

  • D3 - surprisingly common to be low in those that are struggling

This is often where I start because it may be the simple solution. Symptoms such a heavy periods, or poor digestion may push me to get these checked sooner rather than later as well. ⠀
If these look good, we dig a little deeper...

2. Adrenal insufficiency (aka burnout)⠀

This is the one of the most common causes of fatigue I see in practice. You may be or have been in "fight or flight" for awhile, bombarding your body with cortisol and adrenaline (those get up and go hormones). It's telling you it has had enough and won't be listening to the signals anymore. Your body has decreased its production of cortisol, affecting your circadian rhythm. ⠀
We need to support your body with adaptogen herbs such as rhodiola, ashwagandha and holy basil and vitamins such as vitamin C, magnesium and Bs to support cortisol production again. ⠀
OR....⠀
We need to calm down your nervous system with nervine herbs such as passionflower or lemon balm to decrease the "fight or flight" response. ⠀
Is this you? 

3. Female hormone imbalances

This is a big topic itself so I'll just be brushing the surface here, but hormones can definitely affect your energy level. ⠀
Do you see a cycle to your fatigue? This could mean it is related to your menstrual cycle and therefore related to imbalances in estrogen and progesterone levels. ⠀
This is normal to see happen to some extent but not to the extent it interferes with your life. I’ve touched on this before but typically we see an increase in energy the week before ovulation (we are more extroverted) and then it decreases before your period (and we are more introverted). But if you feel so wiped several days before your period we assume either progesterone is low (do you also have spotting before your period?) or estrogen is too high (crazy mood swings or breast tenderness as well?) creating an imbalance. ⠀
What is great is that we can test these hormones through blood or urine with the DUTCH test and there are many great herbs and more natural modalities such as acupuncture that can help balanced it all out. 

Any of these signs common to you? Let’s explore together.

In health & happiness,

Dr. Karen